From: Tom Lane <tgl@sss.pgh.pa.us>
To: Stuart Bishop <stuart@stuartbishop.net>
Cc: pgsql-performance@postgresql.org <pgsql-performance@postgresql.org>
Subject: Re: A pessimistic planner
Date: Fri, 21 Nov 2014 00:12:05 -0500
Message-ID: <21114.1416546725@sss.pgh.pa.us> (raw)
In-Reply-To: <CADmi=6PBw=vUD5S7fgLaMvdGRpmxSqJ4FMap8-4cZGyW-4JYgQ@mail.gmail.com>
References: <CADmi=6PBw=vUD5S7fgLaMvdGRpmxSqJ4FMap8-4cZGyW-4JYgQ@mail.gmail.com>
List-Unsubscribe: <mailto:majordomo@postgresql.org?body=unsub%20pgsql-performance>
Stuart Bishop <stuart@stuartbishop.net> writes:
> I was wondering if the planner should be much more pessimistic,
> trusting in Murphy's Law and assuming the worst case is the likely
> case? Would this give me a much more consistent system?
Well, it would give uniformly awful plans for cases where fast-start
plans are actually useful ... and there are plenty.
We do need to think of ways to account for risk, but I don't think
that jamming the tiller all the way over is likely to be a net
improvement.
regards, tom lane
--
Sent via pgsql-performance mailing list (pgsql-performance@postgresql.org)
To make changes to your subscription:
http://www.postgresql.org/mailpref/pgsql-performance
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Reply to all the recipients using the --to and --cc options:
reply via email
To: pgsql-performance@postgresql.org
Cc: tgl@sss.pgh.pa.us, stuart@stuartbishop.net
Subject: Re: A pessimistic planner
In-Reply-To: <21114.1416546725@sss.pgh.pa.us>
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
This inbox is served by DDX for PostgreSQL; see mirroring instructions
for how to clone and mirror all data and code used for this inbox